Logic
Clear reasoning from the ground up — true/false, if-then, proof, and spotting bad arguments. The thinking that sits under all code and math.
Basic
What Logic Actually Is Logic is the skill of working out what follows from what — the quiet foundation under every line of code, every proof, and every argument you'll ever need to judge. This is where it starts.
Propositional Logic The algebra of true and false: how AND, OR, and NOT combine statements, how truth tables prove what a compound claim really does, and the equivalences (like De Morgan's laws) that let you rewrite and negate conditions with confidence.
Implication & Conditionals 'If P then Q' is the most misunderstood idea in logic. This guide nails what it really means (and when it's true), untangles converse/inverse/contrapositive, and makes the difference between necessary and sufficient conditions finally click.
Predicate Logic & Quantifiers Propositional logic treats whole statements as atoms. Predicate logic looks inside them — at properties of things and the words 'for all' and 'there exists' — which is how you say precise things about whole collections at once.
Boolean Algebra & Logic Gates The same AND/OR/NOT you already know, turned into an algebra you can compute with — and then etched into hardware as logic gates. This is the bridge from 'true and false' all the way down to how a CPU adds two numbers.
What a Proof Is A proof isn't intimidating ceremony — it's an argument so airtight it leaves no room for doubt: a chain of valid steps from things you already accept to the thing you're claiming. Here's how proofs actually work, including the famous techniques.
Critical Thinking & Fallacies A fallacy is an argument that feels convincing but is logically broken. Learning to name the common ones — and the habits of clear thinking that beat them — is the most practical self-defense there is against being misled.